Territory within a district may be withdrawn therefrom in the following manner and upon the following conditions: The petition for withdrawal shall be in writing and shall designate the boundaries of the territory proposed to be withdrawn from the district and shall be signed by at least twenty-five percent of the qualified voters residing within the territory so designated who are qualified voters on the date of filing such petition. The petition shall set forth that the territory proposed to be withdrawn is of such location or character that water and sewer services cannot be furnished to it by the district at reasonable cost, and shall further set forth that the withdrawal of such territory will be of benefit to such territory and conducive to the general welfare of the balance of the district.